Screw press



April 19, 1966 A. H. BURNER 3,246,597

SCREW PRESS Filed May 27, 1965 @y ANDRE H. BURNER s y 22mm/Edi NvENToR BYMMM@ ATTORNEYS United States Patent() 3,246,597 SCREW PRESS Andre H. Burner, Piqua, hio, assignor to rl`he French Oil Milll Machinery Company, Piqua, Ohio, a corporation-of ()hio Filed May 27,1963', Ser. No'. 283,518 3 Claims. (Cl; 100e-145) This application is acontinuation-in'part of'copending application Serial No. 157,127,` -filed December 5, 196.1, now aband`oneda- This inVention-relates-to screw presses, particularly high pressureexpressing pressesl capable of continuous operation, and to a novel feeding arrangement for such presses which enables' them to operate on material containing long stringy or string-like fibers.

In the screw presseswhich are used to express oils or other fluids from nuts, meals, etc.,.the press comprises a main body or cage with drainage openings' through the side walls.y The cage is of a relatively theavy or sturdy construction, capable of holding material therein under high pressures, for example in the neighborhood of one thousand to twenty thousandv p.s.i. The material is fed through the press, and pressure" is exerted upon it, by one or more pressure worms including screw flights which are mounted on and rotate with a drive shaft extending longitudinally through the cage, such screw flights' having a rather close fit with the walls of.' the cage such that when they are rotated they press the material toward the discharge end of the cage. One or more breaker bars, or other suitable stationary or' equivalent obstructing members are provided between the pressure worms to afford a restriction and a barrier to rotation of the flow of material, thus providing a means against which the material :is pressed to obtain the desired high mechanical pressure. Under this pressure the fluids are expressed from the material and pass outwardly through the drainage' openings, while the material solids are retained in the cage body.

The aforementioned pressing structure is usually fed by a feed worm which packs' the material into the first of the pressure worms mounted within the cage. The feed worm receives the material from an inlet hopper, into which the material is dropped, or sometimes fed under a relatively low mechanical pressure, for example, a few pounds per square inch, and the feed worm takes up this material and Carries it into the cage body. The worm may be rotated at a somewhat greater speed than the pressure worms, or its pitch may be different, so that the feed worm functions in the desired manner to' compact the material initially and feed under some pressure into the first pressure worm.

When operating such a press upon materials of a fibrous nature, particularly materials having long stringl-ike or stringy fibers such as raw sugar cane fibers, sugar cane wh-ich has been torn or cut initially into suitable lengths, or cane bagasse (so called lbecause it is bagasse obtained Ifrom the mills after a certain amount of juice is extracted from cane), these materials have `been observed to clog at and around the area where the flight or flights of the feed worm pass from the hopper inlet into the entrance area of the main cage.

In this area, the stringy fibers fall or otherwise bridge over the edges of the flight of the feed screw, and collect in such fashion that they jam against the cage body, in other words between the peripheral edge of .the flight on the feed screw and the interior surface of the cage. These collecting fibers produce such a vhigh load upon the shaft, `resisting turning thereof, that they cause erratic operation of the press, with the result that they initially produce a high turning load, with relatively low throughput capacity, until such time as the fibers are cut, sheared, or torn in this area, whereupon the load upon the feed screw ice ing a 200 horsepower motor with an impressed electrical potential of about 440 volts.

In accordance with the invention the collecting,.bridg ing, and jamming of' the fibers around; the feed screw flight, and between such. flight andy the cage walls, is avoided' by providing la substantial spacing between the peripheral edge of the feed screw flight and the surrounding cage wall. For example, it has been customary practice in the past, inpressesconstructed as described above, to aflord a clearance between the feed screw flight and the cage wall of approximately one thirty-secondof an inch. Thislclearancefis, whenoperating with thestringy fibrous materials, not sufficient to prevent the jamming and erratic operating conditions mentioned as. producing the fluctuating load upon thepress. It has been found, however, that although it would not be expected,A an increase in this clearance will obviate the jamming and load fluctuation conditions while. still maintaining an effective feed of the material. Such an. arrangement is unknown inthe art, and contrary to priorv teachings according to which it would be expected that anincrease in feed worm clearance would. in .turn result in an, ineffective feeding operation, with much of the material passing back around the feed'y worm and failing to carry forward into theflrst pressure worm. It has been discovered that with an, increase inv feed wormv clearance to provide a spacing in the order of one-half of an inch or more (satisfactory results having been obtained with upwards of seven-eighths of an inch clearance). an effective continuous feed of this fibrous material is maintained,A and the load on the press drive is even, instead of` fluctuating.

Accordingly, `the primary object. of this inventionl is to provide a novel feeding arrangement for high pressure screw presses, permitting effective continuous feed of stringy fibrous material into the press.

Another object of the invention is to provide a high pressure continuous press feed arrangement in which the feed worm initially carrying material into the press extends into the barrel of the press and has an unusually large clearance with respect to the walls of thepress barrel, andV in which' such feed worm functions to force fibrous material into the-first pressure worm of the press whichv has normal minimal clearance.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawingv and the appended claims.

In the drawing, FIG. 1 is a vertical sectional view, with some parts in elevation, .taken along the vertical center line of an interruptedflight high pressure screw press Constructed in accordance with the invention.

Referring to the drawing, the press structure includes a main framel 10 including a collection pan 12 which receives expressed liquids,l which may be discharged through the elbow 13. The main cage or barrel' of the press -is formed by an outer cage section 15 which is mounted to swing from the rod 16. There are two such sections, normally bolted together, however the drawing shows the cage opened, i.e., with the sections separated, and the nearer section removed. Details of a suitable cage construction are well known in the art, and may be found, for example in United States Patent Nos. 2,421,763; and

2,320,765, both assigned to the same assignee as this ap- These lugs cooperate with collars 27, which may or may not be tapered, as desired, to form between them z-ones wherein the material is caused to move axially of the cage, and the material is packed into and forced through these zones by the preceding pressure worms 30. The worms and the collars are mounted upon a drive shaft 32, the end of which is shown extending into its splined drive sleeve 33. The collars and worms are held on the shaft by the end nut 35, and the worms have the normal minimal clearance with the cage walls, in the order of one 'thirty-second of an inch.

The inlet to the cage is formed by a vertical hopper or feed opening 40, which opens into the inlet chamber or section 42 of the cage. Suitable screen bars 43 may also be mounted to form portions of the walls of the chamber providing for passage of liquids expressed in this initial sec-tion of the press.

A feed worm 45 is mounted on the main shaft 32, extending through the feed hopper and the entrance area of the press, and abutting the first pressure worm 30. Preferably, the feed worm is rotatable independently of the shaft, and it is driven by a collar 46 which engages through one or more drive pins 47 with the quill or sleeve 48. Such a construction provides for a faster rotation of the feed worm 45 in those constructions where such an arrangement is desired.

Feed worm 45 is provided with one or more conveying flights 50. These ights are preferably continuous from one end to the other of the feed worm body. Depending upon whether it is advantageous to drive the feed worm at a faster rate than the pressure worms, or at the same rate, the pitch of the feed worm may be substantially different from the pressure worm pitch. For example, it is possible to obtain the desired packing or feeding action from the feed worm in some cases by driving it directly from the shaft 32 while increasing the pitch of the feed worm flight. The advantages and disadvantages of these feed worm constructions are known to those skilled in the art.

In accordance with this invention, however, the clearance between the periphery of the feed worm flight 50 and the inner walls of the cage inlet section 42 is significantly greater than the clearance normally employed. For example, normal running clearance in prior art presses is approximately one thirty-second of an inch. Attempts `have Ibeen made to relieve the erratic operation previously mentioned by increasing the running clearance of the feed worm ight by approximately dou-ble the normal minimal clearance, in other words by an increase t approximately one-eighth inch clearance. It has been discovered, however, that even this much increase in clearance was not effective in alleviating the condition, and therefore in accordance with the invention the clear ance between the ight 50 and the inlet section walls is in the order of approximately one-half of an inch, and satisfactory results have been obtained with a clearance up to approximately seven-eighths of an inch. This clearance is considered to -be substantial in this art, since it is clear from the foregoing exemplary dimensions that even a clearance of one-half of an inch is about sixteen times the usual running clearance. It may be mentioned also, that in suitable arrangements of the invention the height of the feed worm flight 50, in other words its ex-tent radially from the worm -body 45, is about two inches.

This clearance is maintained throughout the length of the feed worm, such that stringy fibers or similar material can bridge or hang over the periphery of the feed worm flight and still be fed forward and packed into the first pressure worm 30 without producing any substantial drag against the walls of the inlet section, and particularly without collecting and jamming between the flight 50 and the inlet section walls. The transition from the greater clearance at the feed worm to the minimal clearance at the first pressure worm should be abrupt, rather lthan gradual as with a tapered worm, and it is preferred, although not necessary to leave an axial gap, as shown at 55, between these worms.

Furthermore, the feed worm extends substantially into the inlet section 42 of the press. In other words, the: feed worm passes across the bottom of the hopper or feedopening 40, and into the inlet chamber or section 42 of the cage having substantial distance, as will be apparent from inspection of FIG. 1. For example, in the embodifment shown the feed worm flight wraps about the body approximately two and one-'half turns. Of this extent of the feed worm, -approximately one-half is beneath the inlet opening 40 and the other half extends into the cage inlet 42, so that the feed worm functions to carry the stringy material well into the cage. It should be under.'- stood that this example is merely illustrative of the invention, and that it is not required to have the feed wor-mx extend for at least half its length into the cage inlet however, there should be more than a slight extension ofthe feed worm into the cage inlet, in other words the length of the feed worm should be substantially greater than the opening in the bottom of the feed lhopper 40. The arrangement can vary with the use of different pitch of the feed worm, as might be desired for example if a feed worm is utilized -at the same rotational speed as the main shaft, since in that case the pitch of the feed worm would preferably lbe changed to produce the desirable higher carrying rate of the feed worm to force the material into the main cage.

Accordingly, with a construction as described above it is possible to handle, and to feed effectively, the materials having string-like fibers of substantial length such as mentioned previously, while maintaining a substantially constant load upon the press and while maintaining a continuous effective conveying of the material through the press.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this preciseI form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. In a continuous screw press adapted to work on fibrous material having fibers of substantially long and string-like character, the combination of a cylindrical main press cage having drainage openings in its walls for passage of uids expressed from the material, -means including pressure worms in said cage extending into closely spaced relation with the walls of said cage for exerting high mechanical pressures on the material, means for rotating said worms during operation of said press in a manner to convey the fibrous material through said cage while exerting pressure thereon, an inlet to said cage including a feed hopper and a cylindrical inlet section extending from the bottom of said feed hopper and substantially beyond the lower end of said hopper into said cage and aligned with said cage for conveying material to the first of said pressure worms, a rotatable feed worm extending across the bottom of said feed hopper and substantially into said inlet section, -a drive for turning said feed worm to take up material from said hopper and carry such material through said inlet section to force such material into said cage, said feed worm having a conveying flight with an outer diameter substantially less than the inner diameter of said inlet section for-ming a relatively wide space in the order of at least one-half inch between the edge of said ight and the wall of said inlet section, said relatively wide space being substantially larger than the space between said pressure worms and said cage to provide for :bridging of long fibers of the material over said flight while maintaining a continuous movement of the fibrous material from said hopper into said main cage.

2. In a continuous screw press adapted to work on fibrous material having fibers of substantially long and string-like character, the combination of ya cylindrical main press cage having drainage openings in its walls for passage of fluids expressed from the material, means including pressure worms in said cage and having a close running clearance therewith in the order of one thirtysecond of an inch for exerting high mechanical pressures on the material, means for rotating said worms during operation of said press in a manner to convey the brous material through said cage and to exert pressure thereon, `an inlet to said cage including a feed hopper and a cy1indrical inlet section extending from said feed hopper substantially into said cage and aligned with said cage for conveying material to the rst of said pressure worms, a rotatable feed worm extending across said feed hopper and substantially into said inlet section and having a drive arranged to turn said feed worm to take up material from said hopper and force such material into said cage, said feed worm having -a conveying flight with a constant outer diameter substantially less than the inner diameter of said inlet section forming a relatively wide space between the edge of said flight and the wall of said inlet section through which space long fibers of the material can extend over the periphery of said flight tio maintain a continuous movement of the fibrous material from said hopper into said main cage and to avoid collection of said long fibers between said feed worm flight and the walls of said inlet section, said wide space between the wall 0f said inlet section and the edge of said feed worm flight being in the order of sixteen to twenty-eight times greater in width than the close running clearance between said pressure worms and the w-alls of said cage.

3. A continuous screw press as dened in claim 1, wherein said lrelatively wide space between the edge of said conveying ight on said feed worm and the wall of said inlet section is in the range of approximately one-half inch minimum width and approximately seveneighths inch maximum width.

References Cited by the Examiner UNITED STATES PATENTS 519,209 5/ 1894 Van Eyck. 1,855,369 4/1932 Tessandori 10U-149 X FOREIGN PATENTS 160,803 1/1955 Australia. 613,378 5/1935 Germany.

WALTER A. SCHEEL, Primary Examiner. 

1. IN A CONTINUOUS SCREW PRESS ADAPTED TO WORK ON FIBROUS MATERIAL HAVING FIBERS OF SUBSTANTIALLY LONG AND STRING-LIKE CHARACTER, THE COMBINATION OF A CYLINDRICAL MAIN PRESS CAGE HAVING DRAINAGE OPENINGS IN ITS WALLS FOR PASSAGE OF FLUIDS EXPRESSED FROM THE MATERIAL, MEANS INCLUDING PRESSURE WORMS IN SAID CAGE EXTENDING INTO CLOSELY SPACED RELATION WITH THE WALLS OF SAID CAGE FOR EXERTING HIGH MECHANICAL PRESSURES ON THE MATERIAL, MEANS FOR ROTATING SAID WORMS DURING OPERATION OF SAID PRESS IN A MANNER TO CONVEY THE FIBROUS MATERIAL THROUGH SAID CAGE WHILE EXERTING PRESSURE THEREON, AN INLET TO SAID CAGE INCLUDING A FEED HOPPER AND A CYLINDRICAL INLET SECTION EXTENDING FROM THE BOTTOM OF SAID FEED HOPPER AND SUBSTANTIALLY BEYOND THE LOWER END OF SAID HOPPER INTO SAID CAGE AND ALIGNED WITH SAID CAGE FOR CONVEYING MATERIAL TO THE FIRST OF SAID PRESSURE WORMS, A ROTATABLE FEED WORM EXTENDING ACROSS THE BOTTOM OF SAID FEED HOPPER AND SUBSTANTIALLY INTO SAID INLET SECTION, A DRIVE FOR TURNING SAID FEED WORM TO TAKE UP MATERIAL FROM SAID HOPPER AND CARRY SUCH MATERIAL INTO SAID CAGE, SAID FEED WORM HAVING A SUCH MATERIAL INTO SAID CAGE, SAID FEED WORM HAVING A CONVEYING FLIGHT WITH AN OUTER DIAMETER SUBSTANTIALLY LESS THAN THE INNER DIAMETER OF SAID INLET SECTION FORMING A RELATIVELY WIDE SPACE IN THE ORDER OF AT LEAST ONE-HALF INCH BETWEEN THE EDGE OF SAID FLIGHT AND THE WALL OF SAID INLET SECTION, SAID RELATIVELY WIDE SPACE BEING SUBSTANTIALLY LARGER THAN THE SPACE BETWEEN SAID PRESSURE WORMS AND SAID CAGE TO PROVIDE FOR BRIDGING OF LONG FIBERS OF THE MATERIAL OVER SAID FLIGHT WHILE MAINTAINING A CONTINUOUS MOVEMENT OF THE FIBROUS MATERIAL FROM SAID HOPPER INTO SAID MAIN CAGE. 